Knowledge of downhole parameters and conditions help drillers make decisions that may increase drilling efficiency and save money. Downhole data acquisition systems may be used by drillers to determine those parameters, such as spatial position, formation type, and the economic potential of a resource. Often, bottom hole assemblies (BHA) will contain sensors that can measure various rock and drilling properties employing acoustic, nuclear, electromagnetic, and other sensing and data acquisition capabilities. At different points in a drilling operation, data from certain sensors may be of a higher interest then data from other sensors.
U.S. Pat. No. 5,959,547 to Tubel et al., which is herein incorporated by reference for all that it contains, discloses a plurality of downhole control systems interconnected by a network including a server for monitoring and controlling network communications. Each downhole control system is associated with a zone in one or more wells. The downhole control systems communicate directly with each other transferring information and commands as necessary. The downhole server monitors network communications to resolve data collisions and provides supervisory functions.
U.S. Pat. No. 6,909,667 to Shah et al., which is herein incorporated by reference for all that it contains, discloses several methods for selecting and transmitting information from downhole source using more than one channel of communication wherein data streams transmitted over each communications channel are each independently interpretable without reference to data provided over the other of the communications channels. Preferred embodiments incorporate the use of a combination of at least two of mud-based telemetry, tubular-based telemetry, and electromagnetic telemetry to achieve improved results and take advantage of opportunities presented by the differences between the different channels of communication.
U.S. Pat. No. 7,142,129 to Hall et al., which is herein incorporated by reference for all that it contains, discloses, a method and system for use in synchronizing at least two clocks in a downhole network. The method comprises determining a total signal latency between a controlling processing element and at least one downhole processing element in a downhole network and sending a synchronizing time over the downhole network to the at least one downhole processing element adjusted for the signal latency. Electronic time stamps may be used to measure latency between processing elements. The system for electrically synchronizing at least two clocks connected to a downhole network comprises a controlling processing element connected to a synchronizing clock in communication over a downhole network with at least one downhole processing element comprising at least one downhole clock. Preferably, the downhole network is integrated into a downhole tool string.